Block $\backslash ($ A $\backslash )$ in $($Figure $1)$ has mass $1\mathrm{.}00$ kg $,$ and block $\backslash ($ B $\backslash )$ has mass $3\mathrm{.}00$ kg $.$ The blocks are forced together, compressing a spring $\backslash ($ S $\backslash )$ between them; then the system is released from rest on a level, frictionless surface. The spring, which has negligible mass, is not fastened to either block and drops to the surface after it has expanded. Block $\backslash ($ B $\backslash )$ acquires a speed of $\backslash (1\mathrm{.}20\backslash$mathrm$\{$~m$\}/\backslash$mathrm$\{$s$\}\backslash ).$

Part A

What is the final speed of block $\backslash ($ A $\backslash )?$

Express your answer in meters per second.

$\backslash [$

v$=\backslash$quad $\backslash$mathrm$\{$m$\}/\backslash$mathrm$\{$s$\}$

$\backslash ]$

Request Answer

Part B

How much potential energy was stored in the compressed spring?

Express your answer in joules.

$\backslash [$

U$=$

$\backslash ]$

Request Answer Figure

$1$ of $1$